U.S. patent application number 13/515725 was filed with the patent office on 2013-01-31 for device for loading solid particles into a chamber.
This patent application is currently assigned to TOTAL RAFFINAGE MARKETING. The applicant listed for this patent is Bernard Cottard, Pascal Leroy, Vincent Mayeur. Invention is credited to Bernard Cottard, Pascal Leroy, Vincent Mayeur.
Application Number | 20130025739 13/515725 |
Document ID | / |
Family ID | 42396429 |
Filed Date | 2013-01-31 |
United States Patent
Application |
20130025739 |
Kind Code |
A1 |
Cottard; Bernard ; et
al. |
January 31, 2013 |
DEVICE FOR LOADING SOLID PARTICLES INTO A CHAMBER
Abstract
The invention relates to a device for loading solid particles
into a vessel, comprising: a means for supplying solid particles to
be distributed, said means pouring said solid particles into a
supply pipe (1), a movable assembly (2) arranged below the supply
pipe (1), comprising a central shaft (3) and deflector elements (5)
which are integral in rotation with said shaft and arranged around
the shaft on multiple vertical tiers (E1-E4) and are articulated
about it in such a way that they can lift up, a supply pipe (1)
surrounding at least partially said central shaft and comprising at
least one orifice (4) for discharging the solid particles which is
arranged on a side and/or horizontal wall, this device being
characterized in that the movable assembly (2) is designed in such
a way as to allow adjustment of the position of the deflector
elements (5) on the central shaft (3) in order to vary its
permeability to the solid particles.
Inventors: |
Cottard; Bernard; (Saint
Romain De Colbosc, FR) ; Leroy; Pascal;
(Montivilliers, FR) ; Mayeur; Vincent; (Honfleur,
FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cottard; Bernard
Leroy; Pascal
Mayeur; Vincent |
Saint Romain De Colbosc
Montivilliers
Honfleur |
|
FR
FR
FR |
|
|
Assignee: |
TOTAL RAFFINAGE MARKETING
Puteaux
FR
|
Family ID: |
42396429 |
Appl. No.: |
13/515725 |
Filed: |
December 2, 2010 |
PCT Filed: |
December 2, 2010 |
PCT NO: |
PCT/FR2010/052593 |
371 Date: |
October 17, 2012 |
Current U.S.
Class: |
141/1 ;
422/310 |
Current CPC
Class: |
B65G 69/0458 20130101;
B01J 2208/00752 20130101; B01J 8/002 20130101; B01J 8/003 20130101;
B01J 2208/00778 20130101 |
Class at
Publication: |
141/1 ;
422/310 |
International
Class: |
B01J 19/00 20060101
B01J019/00; B65B 1/04 20060101 B65B001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 21, 2009 |
FR |
09 59289 |
Claims
1. Device for loading solid particles into a vessel, comprising: a
means for supplying solid particles to be distributed, which can be
arranged on the upper part of the vessel to be loaded, said means
pouring said solid particles substantially vertically into a supply
pipe, a movable assembly arranged below the supply pipe entirely or
partly inside the vessel, comprising a substantially vertical
central shaft driven in rotation by a driving means and deflector
elements which are integral in rotation with said shaft and are
arranged around the shaft on multiple vertical tiers, these
deflector elements being articulated in such a way that they can
lift up under the effect of the rotation of the movable assembly, a
supply pipe surrounding at least partially said central shaft and
comprising at least one orifice for discharging the solid particles
which is arranged on a side and/or horizontal wall, this device
being characterized in that the movable assembly is equipped with
at least one movable annular support which supports the deflector
elements of at least one tier of deflector elements, this movable
annular support being mounted in sliding fashion on the central
shaft.
2. Device according to claim 1, characterized in that the movable
assembly comprises a plurality of movable annular supports sliding
on the central shaft independently of one another.
3. Device according to claim 1, characterized in that the movable
assembly is equipped with a movable annular support which supports
the deflector elements of the highest tier or the deflector
elements of the other tiers, this movable annular support being
mounted in sliding fashion on the central shaft, and with a fixed
annular support which supports the remaining deflector
elements.
4. Device according to claim 3, characterized in that the movable
annular support is connected to the fixed annular support by at
least one control rod fixed perpendicularly to said annular
supports, said control rod sliding in an orifice provided for this
purpose in either the fixed or movable support, and being integral
with the other fixed or movable support, the distance between the
two highest tiers being adjusted by sliding of said control
rod.
5. Device according to claim 4, characterized in that the control
rods are provided with stops limiting the maximum spacing between
the fixed and movable annular supports.
6. Device according to either of claim 4, characterized in that a
spring is mounted around each control rod so that it is compressed
when the movable annular support is brought closer to the fixed
annular support.
7. Device according to claim 1, characterized in that it comprises
means for controlling the relative displacement of the movable
annular supports making it possible to adjust the distance
separating them.
8. Device according to claim 1, characterized in that it comprises
at least one lever which can exert pressure on the movable annular
support, the lever comprising a vertical part that slides parallel
to the rotary shaft and is articulated with an actuating arm, the
free end of the vertical part bearing against the upper face of the
movable annular support.
9. Device according to claim 1, characterized in that it comprises
a ring surrounding the supply pipe and sliding along the latter, on
which is fixed at least one rod extending parallel to the rotary
shaft in the direction of the deflector elements, the free end of
the rod being shaped so as to bear against the upper face of the
movable annular support, at least one screw bearing on the ring
allowing the latter to be displaced vertically.
10. Method for loading reactors, in particular those used in the
oil, chemical or petrochemical industry, employing the device
according to claim 1, in which the position of the deflector
elements on the central shaft and the rotational speed of the
movable assembly are adjusted depending on the loading height in
order to improve the flatness of the loading profile.
11. Method for loading a reactor according to claim 10, in which
the distance between the two highest tiers of deflector elements of
the device is adjusted.
12. Method for loading a reactor according to claim 11, in which
the distance between the two highest tiers of deflector elements is
at its maximum at the beginning of loading and at its minimum at
the end of loading.
13. Method for loading a reactor according to claim 11, in which
the distance separating the two highest tiers is between 0 and 150
mm.
14. Method for loading a reactor according to claim 10, in which
the rotational speed of the deflector elements is between 25 and
250 rpm.
Description
[0001] The invention relates to a device for loading solid
particles into a vessel which makes it possible in particular, by
adjusting the permeability of the movable assembly required to
disperse the particles, to improve the shape of the loading
profiles of the vessel depending on the rotational speed of said
movable assembly.
[0002] The invention relates more particularly to the loading of
fixed-bed reactors, especially those used in the chemical,
electrochemical, oil or petrochemical industries, with divided
solid particles which can, for example, take the form of spheres,
granules, cylinders, pellets, rods or any other form and which
generally are relatively small in size.
[0003] The particles can in particular be molecular sieves or
granules of solid catalysts, generally extruded, which either have
an irregular shape or are in the form of mono- or multi-lobed rods
or spheres, the dimensions of which can vary depending on
circumstances from a few tenths of a millimetre to a few
centimetres.
[0004] Reference will be made more particularly in the remainder of
this description to this so-called application of "dense loading"
catalyst granules into a chemical reactor but the device according
to the invention can be applied to the loading of any other type of
solid particles into any type of vessel.
[0005] "Dense loading" is understood to mean in the sense of the
present invention optimized loading with a sprinkling effect so
that the maximum amount of solid particles can be loaded
homogeneously and as uniformly as possible into a minimum amount of
space within a minimum amount of time.
[0006] A certain number of methods and devices are known which make
it possible to increase the density of a fixed bed of catalyst
particles in a chemical reactor. These methods have in common that
the particles to be loaded are introduced from the top of the
reactor and that as the individual particles drop down they collide
with fixed or movable mechanical deflectors which cause said
particles to be diverted in a random fashion. The particles which
have been deflected from their downward path as they drop ideally
fall individually and freely with a sprinkling effect over the
entire surface of the filling front where they form a dense and
homogeneous deposit.
[0007] The Applicant, as part of its attempts to optimize these
systems for loading reactors, has developed a filling device that
makes it possible, by virtue of a movable assembly intended to
disperse the solid particles and which comprises flexible
deflectors articulated about a rotary shaft such that they can lift
up under the effect of the rotation of the movable assembly, to
considerably reduce the steric hindrance of the system of
deflectors and to facilitate its installation in the reactors. This
basic system is described in patent application EP 0 007 854 and
improvements to this filling device are disclosed in applications
EP 0 116 246, EP 0 769 462 and EP 1 776 302.
[0008] Even when a set of high-performing deflectors is used, the
behaviour of the catalyst particles during the filling of the
reactor may differ from the ideal behaviour described above. The
"filling front", also called the "loading profile", in other words
the interface between the catalytic bed and that part of the
reactor which has not yet been filled, can sometimes deviate
substantially from the horizontal and/or have bumps and/or hollows
on said filling front. The catalyst particles, in particular when
they have an anisotropic form, can position themselves in favoured
directions, thus creating preferred paths for the liquid load and
the reactive gas to pass through the catalytic bed. This can result
in the reactor operating in an unsatisfactory manner, for example
in terms of hydrodynamics, and ultimately can represent a cost for
the operator.
[0009] The unsatisfactory filling fronts can partly be corrected by
modifying the rotational speed of the movable assembly. In general,
this rotational speed is increased as the filling proceeds so that
the particles are sent as close to the walls as possible. However,
the permeability of the movable assembly is highly dependent on the
rotational speed: an increase in speed being translated by a marked
decrease in permeability. This can result in an absence, in
particular a partial one, or a lower density of catalyst particles
at certain points of the cross section of the reactor. This
absence, for example a partial one, or this lower density can in
particular be distributed in a concentric ring relative to the axis
of rotation of the movable assembly.
[0010] Within the sense of the present invention, the permeability
of the movable assembly is defined as the proportion of the weight
of the solid particles passing through the said assembly without
being deviated by it, over the total weight of particles loaded,
and can commonly vary from 0% to 50% by weight.
[0011] In the course of its extensive research into the technology
of the dense loading of solid particles into a vessel, and in
particular granules of catalyst into chemical reactors of different
heights and loading diameters, the Applicant has noticed that by
modifying the movable assembly, by varying the number of
deflectors, the shapes and dimensions of the latter, the vertical
spacing between the deflectors and/or their relative positions, it
was possible to improve the profiles for a given drop height.
However, for a different drop height, these modifications on the
contrary result in a deterioration of the profile.
[0012] One solution could consist in modifying the deflectors as
the filling proceeds. However, this solution entails stopping the
loading and an operator going down into the reactor to change the
deflectors before the loading can resume. Such a solution is not
very practical as it is too long and complex to implement.
[0013] The Applicant has discovered that simply by modifying the
position of the deflectors, and in particular the distance
separating the two upper levels of deflectors, depending on the
rotational speed of the movable assembly, it was possible to
improve the flatness of the loading profile independently of the
drop height of the particles.
[0014] The Applicant has thus developed a device which, while it is
based on the same principle as the dense loading system (known as
"Densicat.RTM.") disclosed in EP 0 769 462, and has the same ease
of operation and installation in the reactor to be loaded, also
makes it possible to improve the loading profiles of any type of
reactor.
[0015] According to a first aspect, the subject of the present
invention is a device for loading solid particles into a vessel, in
particular homogeneously and uniformly, comprising: [0016] a means
for supplying solid particles to be distributed, which can be
arranged on the upper part of the vessel to be loaded, said means
pouring said solid particles substantially vertically into a supply
pipe, [0017] a movable assembly arranged below the supply pipe
entirely or partly inside the vessel, comprising a substantially
vertical central shaft driven in rotation by a motive means and
deflector elements which are integral in rotation with said shaft,
are arranged around the shaft on multiple vertical tiers and are
articulated about it in such a way that they can lift up, [0018] a
supply pipe surrounding at least partially said central shaft and
comprising at least one orifice for discharging the solid particles
which is arranged on a side and/or horizontal wall,
[0019] this device being characterized in that the movable assembly
is designed such that the position of the deflector elements on the
central shaft can be adjusted in order to vary its permeability to
the solid particles.
[0020] The position of the deflector elements on the central shaft
is understood to mean the position of these elements in a vertical
direction, in other words along the central shaft.
[0021] This position can be adjusted by translational movement of
the deflector elements in a direction parallel to the axis of the
central shaft.
[0022] The movable assembly can thus be equipped with at least one
movable annular support which supports the deflector elements of at
least one tier of deflector elements, this movable annular support
being mounted in sliding fashion on the central shaft.
[0023] The movable assembly can also comprise a plurality of
movable annular supports that slide on the central shaft
independently from one another.
[0024] The deflector elements of the same tier will preferably be
displaced simultaneously.
[0025] More precisely and for one type of said adjustment, the
movable assembly is designed so as to allow a relative displacement
of the two highest tiers of the assembly so that the distance
separating these two highest tiers can be modified.
[0026] By adjusting the distance between the two highest tiers of
the movable assembly, it is possible to modify the permeability of
the latter depending on the rotational speed of the assembly and
the drop height, which makes it possible to correct the loading
profile by improving its flatness.
[0027] In a first embodiment, the highest tier is fixed, the other
tiers being capable of translational movement along the rotary
shaft, integrally with one another.
[0028] In a second embodiment, the highest tier is capable of
translational movement along the rotary shaft, the other tiers
being fixed.
[0029] The movable assembly is advantageously equipped with a
movable annular support which supports the deflector elements of
the highest tier or the deflector elements of the other tiers, this
movable annular support being mounted in sliding fashion on the
central shaft, and with a fixed annular support which supports the
remaining deflector elements.
[0030] The relative displacement of the two highest tiers can thus
be obtained very simply.
[0031] It could also be envisaged that more than one tier of
deflector elements, or even all the tiers, are capable of
translational movement. This movability could, for example, be
achieved by means of a plurality of movable annular supports
sliding on the central shaft, preferably independently of one
another. This relative displacement of the movable annular supports
can be achieved, and controlled, by the means described below with
reference to a single movable annular support. However, other means
for controlling the relative displacement of the movable annular
supports can be envisaged.
[0032] The movable annular support is advantageously connected to
the fixed annular support by at least one control rod fixed
perpendicularly to said annular supports, said control rod sliding
in an orifice provided for this purpose in either the fixed or
movable support and being integral with the other fixed or movable
support, the distance (d) between the two highest tiers being
adjusted by sliding of said control rod.
[0033] The device preferably comprises at least two control rods,
or alternatively at least three control rods distributed regularly
about the central shaft.
[0034] The control rods can be provided with stops limiting the
maximum spacing between the fixed and movable annular supports.
[0035] More particularly, a spring can be mounted around each
control rod so that it is compressed when the movable annular
support is brought closer to the fixed annular support.
[0036] This arrangement has the advantage of only requiring
pressure on the movable annular support to control the distance
between the two upper tiers, releasing this pressure causing the
spacing apart of the two supports under the action of the
spring.
[0037] The device advantageously comprises means for controlling
the relative displacement of the two highest tiers which makes it
possible to adjust the distance separating them.
[0038] Adjustment of the permeability can thus be effected very
simply without having to interrupt the loading of the
particles.
[0039] In a first variant, these control means can consist of at
least one lever which can exert pressure on the movable annular
support, the lever comprising a vertical part that slides parallel
to the rotary shaft and is articulated with an actuating arm, the
free end of the vertical part bearing against the upper face of the
movable annular support.
[0040] In another variant, the control means can consist of a ring
surrounding the supply pipe and sliding along the latter, on which
is fixed at least one rod extending parallel to the rotary shaft in
the direction of the deflector elements, the free end of the rod
being shaped such that it bears against the upper face of the
movable annular support, at least one screw bearing on the ring
allowing the latter to be displaced vertically.
[0041] According to yet another of its aspects, the subject of the
invention is a method for loading reactors, in particular those
used in the oil, chemical or petrochemical industry, employing the
device according to the invention, in which the position of the
deflector elements on the central shaft and the rotational speed of
the movable assembly are adjusted depending on the loading height
in order to improve the flatness of the loading profile.
[0042] Adjusting just these two parameters, and possibly the
openings of the discharge orifices of the supply pipe, makes it
possible to improve the loading profile.
[0043] The method according to the invention can be implemented by
means of a data-processing system, for example a computer (or a
processor) programmed appropriately, this system being configured
in order to displace the deflector elements along the central
shaft, for example via the means for controlling the relative
displacement of the annular supports, and in order to adapt the
rotational speed of the central shaft, for example via controlling
the driving means of the central shaft.
[0044] In a particular embodiment, the distance between the two
highest tiers of deflector elements of the device is adjusted.
[0045] The distance between the two highest tiers of deflector
elements is advantageously at its maximum at the beginning of the
loading and at its minimum at the end of the loading.
[0046] The distance separating the two highest tiers is, for
example, between 0 and 150 mm, preferably between 10 and 75 mm.
[0047] The rotational speed of the deflector elements is, for
example, between 25 and 250 rpm, preferably between 40 and 200
rpm.
[0048] The invention is now described with reference to the
attached drawings which are not limiting and in which:
[0049] FIG. 1 is a diagrammatic view of a device that is the
subject of the present invention,
[0050] FIG. 2 is a view in profile of the annular supports and the
tiers of deflector elements of the movable assembly of a device
that is the subject of the present invention, and
[0051] FIGS. 3a and 3b are diagrammatic views of half of the device
that is the subject of the invention and is equipped with a first
embodiment of the means for controlling the distance between the
two upper tiers, the latter being spaced apart in FIG. 3a and
brought closer together in FIG. 3b,
[0052] FIGS. 4a and 4b are diagrammatic views of half of the device
that is the subject of the invention and is equipped with a second
embodiment of the means for controlling the distance between the
two upper tiers, the latter being spaced apart in FIG. 4a and
brought closer together in FIG. 4b,
[0053] FIGS. 5 and 6 show the loaded height of granules of
catalysts depending on the radius of the loaded vessel obtained
respectively for test 1 and test 2.
[0054] In the loading device of the present invention, the
particles of catalyst coming from the supply means, which can be a
hopper or the like, fall down under the effect of gravity into the
supply pipe, in other words between the inner walls of said supply
pipe. The supply pipe comprises at its base at least one discharge
orifice situated above the movable assembly and more particularly
above the dispersion system formed by the deflectors. The particles
thus fall at least partly onto said dispersion system driven in
rotation by the central shaft via the discharge orifice.
[0055] In addition to a first supply with solid particles being
made through the supply pipe above the movable assembly, at least
one additional supply can be made. This additional supply can be
effected via orifices formed in the supply pipe and arranged on its
vertical and/or horizontal walls. Particles can thus fall onto
parts of the deflectors that are remote from the driving shaft.
This can increase the homogeneity of the distribution of the
particles in the vessel at a great distance from the centre axis. A
judicious choice of the opening or openings can make it possible to
selectively fill densely and homogeneously any portions of the
vessel that are offset relative to the axis of the movable
assembly.
[0056] The motor which drives in rotation the tubular central shaft
of the device of the invention is preferably offset relative to
this shaft and can be supplied with any compressed gas, for example
air or nitrogen. Transmission of the rotary movement of the driving
means to the tubular shaft can be effected by any appropriate known
means, for example by a belt, a chain, a set of gearwheels or by a
combination of these means.
[0057] The central shaft used in the present invention can be solid
or hollow, as described in EP 1 776 302. This latter feature can
offer the advantage of being able to provide a passage through said
central shaft, for example and not implying any limitation, in
order to house in it apparatus for measuring the progression in the
level of the catalytic bed during loading and/or in order to suck
up any catalyst dust emitted during this same loading.
[0058] The device in FIG. 1 comprises a supply hopper (not shown)
arranged above the reactor and which supplies by gravity the supply
pipe (1) with particles of catalyst.
[0059] In this supply pipe (1), the shaft (3) of the movable
assembly (2), driven in rotation by a driving means (not shown), is
arranged substantially on the longitudinal axis of a circular
reactor.
[0060] The granules of catalyst fall under gravity via discharge
orifices (4) formed in the side and/or horizontal walls of the
supply pipe (1), onto the dispersion system consisting of deflector
elements (5) fixed to the rotary shaft (3) and distributed over 4
vertical levels along the axis of rotation (3).
[0061] The surface area of these discharge orifices (4) can
generally be adjusted via a flap (not shown) that slides manually
or automatically to block more or less partially the discharge
opening according to the required rate of flow of the particles for
the loading.
[0062] In this FIG. 1, the deflector elements (5) are arranged
about the shaft (3) on multiple vertical tiers E1, E2, E3, E4 and
articulated on the shaft (3) so that they can lift up under the
effect of the rotation of the movable assembly. These deflector
elements can be distributed evenly at each tier.
[0063] FIGS. 1 to 4 show a device in which the movable assembly is
provided with 4 tiers of deflector elements. An assembly could,
however, also be envisaged with 2 tiers of deflector elements or
more, and preferably with three or four, the fixed tiers being
spaced apart from one another by a distance that lies between 2 and
20 centimetres and preferably between 4 and 10 centimetres.
[0064] The deflector elements can be formed by strips with
longitudinal dimensions that can lie between 10 centimetres and 2
metres, and preferably between 10 cm and one metre. The strips can
also have any shape known from the prior art, namely, for example,
rectangular, triangular or trapezoidal.
[0065] Each tier of deflector elements can comprise at least two
deflector elements, preferably from four to twelve and still more
preferably eight deflector elements, these deflector elements being
arranged about the axis of rotation and preferably having identical
shapes. In particular, the Y deflector elements are each arranged
at 360/Y.degree. to one another.
[0066] The material constituting the strips or the deflector
elements can be a semi-rigid material, preferably flexible rubber
reinforced by a textile fibre, and its thickness can vary between 2
mm and 10 mm and preferably between 3 and 8 mm.
[0067] According to the invention, the movable assembly is equipped
with a movable annular support which supports the deflector
elements of the highest tier or the deflector elements of the other
tiers, this movable annular support being mounted in sliding
fashion on the central shaft (3), and with a fixed annular support
which supports the remaining deflector elements.
[0068] FIG. 2 shows a particular embodiment in which the movable
annular support (10) is that which supports the deflector elements
(5) of the highest tier E1 of the movable assembly. The fixed
annular support (11) supports the deflector elements of the other
tiers, namely of the tiers E2, E3 and E4 in the example shown in
FIGS. 1 to 4.
[0069] The movable annular support (10) is connected to the fixed
annular support (11) by at least two control rods (12) fixed
perpendicularly to the annular supports (10, 11).
[0070] These control rods (12) project above the tiers of deflector
elements. They slide in orifices (13) provided for this purpose in
the fixed support (11) and are integral with the movable support
(10). Thus the distance (d) between the two highest tiers is
adjusted by displacing the control rods (12).
[0071] In the example shown, each control rod (12) is provided with
a stop (14) limiting the maximum spacing between the fixed and
movable annular supports.
[0072] A spring (15) is furthermore mounted around each control rod
(12) so that it is compressed when the movable annular support is
brought closer to the fixed annular support.
[0073] This compression of the springs (15) is, for example,
achieved by exerting pressure on the movable support (10) (and/or
on the control rods (12) in a direction that brings the movable
support and the fixed support closer together). Releasing this
pressure then moves the movable support further away under the
action of the springs (15).
[0074] The distance (d) between the tiers E1 and E2 is thus
adjusted very easily. The sliding of the control rods (12) along
their axis could also be controlled directly in order to adjust
this distance (d).
[0075] In a variant that is not shown, it could be envisaged that
the annular support (11) of the lower tiers E2, E3 and E4 is
movable, the annular support (10) of the upper tier E1 then being
fixed. In this case, the control rods (12) slide in orifices
provided in the fixed annular support (10) and are integral with
the movable annular support (11). Pressure must then be exerted on
the control rods (12) or on the annular support (11).
[0076] The pressure on the movable annular support can be exerted
in different manners.
[0077] In a first variant, shown in FIGS. 3a and 3b, at least one
lever (20) is used which can exert a pressure on the movable
annular support (10).
[0078] This lever (20) comprises a vertical part (21) which slides
parallel to the rotary shaft (3) and is articulated with an
actuating arm (22), the free end of the vertical part bearing
against the upper face of the movable annular support (10).
[0079] The actuating arm (22) extends radially in a direction
moving away from the central shaft (3). It is sufficiently long to
project from the supply pipe (1) and can bear against the lower end
of the latter, as can be seen in FIGS. 3a and 3b.
[0080] A return device, of the spring type (37), can optionally be
provided for returning the lever into a position in which the
distance between the fixed and movable annular supports is at its
maximum. This return device is, for example, fixed between the
fixed and movable annular supports, as shown in FIG. 3a.
[0081] In the example shown, the movable annular support (10)
supports the deflector elements of the tier E1. However, it could
also be provided that the movable support is the one which supports
the deflector elements of the other tiers (E2 to E4).
[0082] In a second variant, shown in FIGS. 4a and 4b, a ring (30)
or collar is used which surrounds the supply pipe (1) and slides
along the latter. This ring (30) preferably slides above the
highest lateral openings (4) of the supply pipe (1).
[0083] On this ring (30), which may be optional, is fixed at least
one rod (31), preferably at least two or three rods, extending
parallel to the rotary shaft (3) in the direction of the
deflectors.
[0084] The free end (32) of each rod (31) is shaped such that it
bears against the upper face of the movable annular support (10),
at least one screw (33), preferably at least two or three screws
(33), bearing against the ring (30) allowing the latter to be
displaced vertically.
[0085] This screw (33) is guided in translational movement by
supports (34) integral with the supply pipe (1) on the side wall of
the latter, outside the pipe, in a zone situated above the openings
(4).
[0086] The rising or lowering of the screw (33) can be actuated by
means of a wheel (35) or by any other suitable means, for example
by hydraulic or pneumatic actuators.
[0087] A return spring (36) can also be provided to return the
screw (33) into a position corresponding to a maximum distance
between the tiers E1 and E2. This spring (36) is, for example,
mounted around the screw (33) and arranged between the ring (30)
and one of the supports (34) of the rod in such a way that, under
the effect of the spring (36), the movable annular support (10)
moves away from the fixed annular support of the lower tiers.
[0088] These embodiments have been described for a device
comprising 4 tiers of deflectors. They can, however, be adapted to
devices comprising at least two tiers of deflector elements.
EXAMPLES
[0089] The Applicant has employed the device that is the subject of
the present invention on a representative model of a typical vessel
of a cylindrical chemical reactor used in its refineries.
[0090] This model has the following dimensions: [0091] height: 5.00
m, [0092] diameter: 3.80 m,
[0093] Conditions Under which the Tests were Carried Out [0094]
type of catalyst: Al.sub.2O.sub.3 impregnated with an organic
liquid in order to obtain a density greater than 0.9, [0095]
average dimensions of the granules of catalyst: trilobed in shape,
1.5 mm diameter and average length 3.5 mm, [0096] quantity of
catalyst loaded: 2 tonnes, [0097] 4 levels of strips, [0098] 8
strips per level, 4 on the last tier, [0099] dimensions of all
strips: length 55 cm, width at narrowest point 7 cm and widest
point 12 cm, thickness 6 mm, [0100] triangular strips as described
in EP 0 769 362, [0101] hollow central rotary shaft.
[0102] Features for Test 1: Configuration at the End of Loading
[0103] The loading was carried out with a movable assembly for
which the distance (d) between the tiers E1 and E2 corresponds to
the normal distance between the two highest tiers, ie d=50 mm, and
with a movable assembly for which the distance (d) between the
highest tiers E1 and E2 is adjusted to d=0 mm (superposition of the
two tiers).
[0104] The conditions under which this test was carried out are as
follows: [0105] feed rate of granules of catalyst to the movable
assembly: =30 T/h, [0106] rotational speed of the movable assembly:
120-125 revolutions per minute, [0107] opening of the 9 lateral and
15 horizontal discharge orifices, [0108] loading time: 2 minutes,
[0109] drop height of the granules of catalyst: 1.5 metres.
[0110] The loading profiles are shown in FIG. 5 in which the height
in millimetres of granules of catalyst loaded during the test is on
the y-axis and the radius in centimetres of the loaded vessel is on
the x-axis. Each of the points that make up the two curves are
average values of the heights measured at different locations of
the corresponding circumference.
[0111] The curve C1 corresponds to the test for which d=50 mm and
the curve C2 corresponds to the test for which d=0 mm.
[0112] In this FIG. 5, the horizontal line at 150 mm on the y-axis
corresponds to the average height of the profile of the curve C1
and the horizontal line at 100 mm on the y-axis corresponds to the
average height of the profile of the curve C2. This makes it
possible to quantify the loading unevennesses with respect to a
theoretical average height.
[0113] The increase in the permeability which results from the
superposition of the tiers E1 and E2 (curve C2) makes it possible
to make up for the unevenness of catalyst that can be seen at r=70
cm on the curve C1. The slight dip in the profile at r=120 cm that
is observed for the curve C2 can be corrected by modifying the
rotational speed and possibly the openings of the machine.
[0114] Features for Test 2: Configuration at the Start of
Loading
[0115] The loading was carried out with a movable assembly for
which the distance (d) between the tiers E1 and E2 corresponds to
the normal distance between the two highest tiers, ie d=50 mm, and
with a movable assembly for which the distance (d) between the
highest tiers E1 and E2 is adjusted to d=73 mm.
[0116] The conditions under which this test was carried out are as
follows:
[0117] feed rate of granules of catalyst to the movable assembly:
=30 T/h, [0118] rotational speed of the movable assembly: 71-72
revolutions per minute, [0119] opening of the 15 lateral and 9
horizontal discharge orifices, [0120] loading time: 2 minutes,
[0121] drop height of the granules of catalyst: 4.3 metres.
[0122] The loading profiles are shown in FIG. 6 in which the height
in millimetres of granules of catalyst loaded during the test is on
the y-axis and the radius in centimetres of the loaded vessel is on
the x-axis. Each of the points that make up the two curves are
average values of the heights measured at different locations of
the corresponding circumference.
[0123] The curve C1 corresponds to the test for which d=50 mm and
the curve C2 corresponds to the test for which d=73 mm.
[0124] In this FIG. 6, the horizontal line at 140 mm on the y-axis
corresponds to the average of the profile of the curve C1 and the
horizontal line at 100 mm on the y-axis corresponds to the average
of the profile of the curve C2. This makes it possible to quantify
the loading unevennesses with respect to a theoretical average
height.
[0125] By moving tier 1 away from tier 2, the permeability of the
movable assembly reduces, which has the consequence of preventing
the over-supply observed at r=70 cm for the curve C1. For the curve
C2, the rotational speed is too high, leading to an over-supply of
catalyst at the walls.
[0126] These tests demonstrate that the use of a device according
to the present invention makes it possible to adjust the
permeability of the movable assembly of the dispersion device by
modifying the distance separating the highest tiers of deflectors
(E1 and E2), and improves very noticeably the loading profile of a
catalytic bed in a chemical reactor or, by extension, the loading
front of solid particles in a vessel.
* * * * *